Challenges have been made to overcome barriers in delivering drugs to malignant brain tumors and treating them. Due to the complex nature and the positional problem of malignant brain tumors which are formed in brains, brain tumors have led to worldwide high mortality.
Among brain tumors, glioblastoma, which is supported by a highly organized and complex network of malignant cells, metastasizes, spreads from the primary lesion to a new area, and rapidly propagates throughout the brain. This rapid proliferation ability of glioblastoma is still present as a significant barrier for conventional treatments such as surgical tumor resection and chemotherapy.
Another main barrier limiting the success rate of chemotherapy is that almost all of the chemotherapeutic agents cannot overcome the inherent defense mechanism of the brain. It has been reported that approximately only less than 1% of chemotherapeutic agents can reach the vasculature of the central nervous system tumors via systemic administration. This is because of the presence of highly selective blood-brain barrier. Overcoming the difficulty of delivering chemotherapeutic agents to a specific region of the brain is a problem in the treatment of brain disorders.
A variety of drug delivery systems (DDS), which are capable of penetrating the blood brain barrier, have been studied. For example, Non Patent Literature 1 discloses that gold particles are used as a blood-brain-barrier-permeable drug delivery system.
Non Patent Literature 2 describes a dual-targeting liposome conjugated with transferrin and arginine-glycine-aspartic acid peptide for glioma-targeting therapy. However, Non Patent Literature 2 does not describe a liposome which comprises a fatty acid as a membrane component.
Non Patent Literature 3 describes a nanoformulation composed of a ribosome inactivating protein, curcin, and a hybrid solid-lipid nanovector for treating glioblastoma. However, Non Patent Literature 3 does not describe nanoparticles to the surface of which substances having specificity to a target cell are bound.